Tool sharpening fixture



March 19, 195? BROWN 2,785,518

TOOL SHARPENING FIXTURE Filed May 25, 1955 I? a v INVENTOR. i /2 ALLEN J. BROWN ATTORNEY TOOL SHARPENING FIXTURE Allen J. Brown, Louisville, Ky.

Application May 25, 1955, Serial No. 510,915

Claims. (Cl. 51220) The present invention relates to a fixture for use with a drill press to hold a tool in proper position while it is being ground to a cutting edge by a grinding wheel held in the chuck of the drill press.

It is the general practice to sharpen cutting tools on a horizontal grinding wheel. This requires, in the case of woodworking hobby shop operators, the purchase of an expensive horizontal axis grinder, and of a fixture to hold the tool while being ground. In the woodworking shop there is little occasion for a grinding wheel except to sharpen tools, so the hobbyist either has to purchase expensive equipment for sharpening his tools, or has to have his tools sharpened by others at considerable exense. p It is an object of the present invention to provide a fixture capable of attachment to a vertical drill press, so that tools can be sharpened thereon without the exercise of great skill.

A further object is the provision of a holding fixture adapted for use on a vertical shaft grinding wheel, which is of simple construction and is relatively inexpensive to manufacture.

The invention is described in the following specification taken in connection with the accompanying drawing illustrating a preferred embodiment of the invention by way of example, and wherein:

Figure l is a perspective view of an embodiment of the invention mounted upon a drill press;

Figure 2 is a plan view of the fixture;

Figure 3 is a section taken on line IllIII of Figure 4, and

Figure 4 is an end elevational view.

Referring to the drawing, there is shown the bed plate 1 of a drill press, on which the grinding fixture is fastened. The grinding fixture has a base plate 2 and a boss or block 3 is suitably secured to the top face of the base plate near the middle. An aperture 4 extends vertically through the base plate and boss. The base plate is attached to the drill press bed plate by a suitable clamping bolt 5 extending through a suitable hole in the bed plate and aperture 4. The base plate 2 provides a keyway or slot 7, and an angle plate 8 has a suitable key 9 received in this slot. Preferably, the slot 7 and key 9 are dovetailed in cross section. The angle plate has a suitable recess 10 to receive the boss 3. A screw threaded stud 11 is received in a screw threaded socket 112 in the boss 3, and this stud passes through a bore 13 in plate 8. A stop collar 14 is pinned to stud 11, and the stud carries a finger knob 15 also serving as a stop collar so the stud does not move axially. By turning the knob 1 to turn the stud, the plate 8 may be shifted in the keyway. Any suitable gibs may be provided to take up play between the keyway and key.

The vertical portion of the plate 8 is cut out at 15 to provide bosses 16 and 17 at the ends of the cut out. A face plate 18 has a boss 19 at one end, and the plates 8 and 18 are hinged together by a suitable pin passing through bosses 16, 19 and 17. The edges of bosses 16 and 17 are suitably chamfered to allow clearance for pivoting of the face plate. Face plate 13 carries a split block 21 in which a spherical socket is formed, and the spherical end 22 of an adjusting screw 23 is received in this socket. The upright portion of plate 8 carries bosses 24 surrounding an opening 25, and a block 26 is suitably pivoted in this opening on vertical pivot pins 27. The screw 23 is threaded through block 26 and carries a hand knob 28 at its end. By turning knob 28 and screw 23, the face plate is rotated on its pivot. The base plate 2 is rabbeted at 29 to accommodate the lower end of the face plate.

The face plate has tapped holes 31 therein, and a clamping bar 32 having bores aligned therewith, is clamped to the face plate by screws 33. A shoulder 34 is formed on the face plate, and the blade 35 to be sharpened, such as the plane blade illustrated, is securely clamped by the screws 33 between the face plate 18 and clamping bar 32, and bearing on shoulder 34. The edge of the face plate may be chamfered, if desired. If desired, a tube 36 may be attached to clamping bar 33 to deliver water or grinding lubricant to the edge being sharpened. The drill press chuck 37, which is vertically movable in known manner, carries a spindle 38 in which is secured the grinding wheel 39.

The operation of the invention now will be described. The spindle 38 carrying a grinding wheel 39 is secured in the chuck 3'? of the drill press. The plane blade 35 is then inserted between the clamp bar 32 and face plate 18 with its lower edge supported on shoulder 34, and the screws 33 are tightened to hold the blade in place. The shoulder 34 is parallel to the bottom of base 2. The fixture is placed on the bed plate 1 of the drill press, is clamped in place by bolt 5, and is adjusted by turning knob 15 to the proper distance so the blade will be engaged by the grinding wheel. Screw 23 is now turned to shift face plate 13 so the grinding wheel will grind the blade at the proper angle, and screw Hil is adjusted so that the grinding wheel makes proper contact with the plane blade. During the grinding operation, the grinding wheel is continuously raised and lowered so as to continuously transverse the blade during grinding, and stud 11 is used to shift the blade as the metal is cut away. The wheel thus grinds a hollow bevel edge on the blade at the correct angle, which is squared relative to the lower reference edge of the blade.

I claim as my invention:

1. A fixture for attachment to a vertical drill press comprising: a base plate having a planar bottom surface adapted to be clamped to the drill press bed plate; an angular plate slidably secured to the base plate; a face plate hinged to the angular plate on a vertical pivot; means for holding a blade to be ground on said face plate; means for adjusting said angular plate horizontally along the base plate; and means for angularly adjusting said face plate about said pivot relative to the angular plate.

2. A fixture as specified in claim 1 wherein: said face plate has a guide shoulder parallel to the bottom of the base plate, against which the blade to be ground engages, for squaring the edge to be ground.

3. A fixture as specified in claim 2 wherein: said face plate has a spherical socket; said angular plate carries a block mounted on a vertical pivot; said means for adjusting the face plate comprises a screw threaded into said block and having a spherical end received in said socket; said angular plate has a recess; a block is positioned in said recess attached to said base plate; and said means for adjusting the angular plate comprises a stud threaded into said block and rotatably anchored in the wall in said recess.

Patented Mar. 19, 1957 4. A fixture as specified in claim 1 wherein: said angular plate has a recess; a block is located in said reee'ss attached to the base plate; and said means for adjusting the angular plate comprises a stud threaded into said block and passing through a wall of said recess.

5. A fixture for attachment to a vertical drill press comprising: a base plate adapted to be clamped to a drill press bed plate; a horizontally adjustable member supported on and slidably secured to said base plate; a face plate hinged to said adjustable member on a vertical pivot; a clamp on said face plate for holding an article to be ground; a first adjustable screw means for moving said member to and holding it in an operative position on said base plate; and a second adjustable 'scre'vii means for moving said face plate to and holding it in an operative position on said member.

References Cited in the file of this patent v UNITED STATES PATENTS 

